Andrew Sutton pisze:
Does "add_vertex" check the existence of added vertices of given
index? No, it doesn't.
Or I do something wrong.
For a short answer: never.
Well, it seemed that sometimes yes.
I looked at the piece of code of add_vertex in a boost/graph header file:
template
inline typename Config::vertex_descriptor
add_vertex(const typename Config::vertex_property_type& p,
vec_adj_list_impl& g_) {
typedef typename Config::vertex_descriptor vertex_descriptor;
Graph& g = static_cast(g_);
if (optional v
= g.vertex_by_property(get_property_value(p, vertex_bundle)))
return *v;
typedef typename Config::stored_vertex stored_vertex;
g.m_vertices.push_back(stored_vertex(p));
g.added_vertex(g.m_vertices.size() - 1);
return g.m_vertices.size() - 1;
}
So, with property defined as follows
property_type: typedef property VIndex;
Undoubtedly, above add_vertex function searches vertex by properties and
should return descriptor of found vertex. Indeed, it doesn't.
I'm a little bit confused.
For a longer answer... It looks like vertices are dynamically allocated
and the vertex set (listS, setS, etc.) stores pointers to those
vertices. In the case of associate containers, the key_type is just the
pionter value. In otherwords, add_vertex will never look for a previous
instance of the vertex.
Andrew Sutton
andrew.n.sutton@gmail.com mailto:andrew.n.sutton@gmail.com
Regards
liquid
